Study of topological morphology and optical properties of SnO2 thin films deposited by RF sputtering technique

Transparent conducting thin films of tin dioxide (SnO2) were prepared on glass substrates by RF sputtering technique. The as-deposited films were annealed at different temperatures (473, 673 and 823 K) for 3 h in air under normal atmospheric pressure. The film structure was characterized using atomic force microscopy (AFM). The optical properties of the prepared and annealed films were studied using their reflectance and transmittance spectra. The Urbach energy was found to decrease with increasing annealing temperature. The estimated direct optical band gap (Egd) values were found to decrease by annealing temperature. The photoluminescence (PL) spectroscopy measurement of the SnO2 film shows that the band to band emission peak atEgPL=4.18 eV. The dispersion curves of the refractive index of SnO2 thin films were found to obey the single oscillator model.